Microsoft and Apple already support RTF in the core OS (and have for a while. Apple's Cocoa framework supports DOC too). All the existing WPs support one if not both of those formats. We already have our interchange formats. DOC may be hard to emit and consume, but RTF is no better or worse than ODF. RTF already is the Esperanto (or lingua-franca, depending on your viewpoint) of the Word Processing world. If we all started speaking ODF instead of RTF tomorrow, pragmatically, nothing really changes.
That's because there already is a standard around which all the WPs measure themselves. And for better or worse, that standard is Microsoft Word. And that standard's file format is RTF/DOC. The WPs of the world are largely competing on quality and not feature creep, built around those standards. In this mindset, all ODF amounts to is a few thousand more lines of code that you'll need to write and support. But having your potential innovations constrained by a large, unresponsive standards body sounds less-than-ideal. As someone who voted "YES" on the recent referendum, I think that you'd show a little sympathy there :) I don't think that we've reached the be-all and end-all of WPs, and any such standard would have to be aware of that.
That said, file formats are boring, just like TCP is. You'll eventually reach some "good enough" state, like RTF or ODF. Like TCP, the cool things are the apps built on top of the formats. Any app that can emit ODF can emit RTF just as easily. Why more don't, I honestly don't know. As more people start using it, I'll continue consume it as happily as I consume DOC and RTF today - they're not going away anytime soon. But I do know that I'd be touting OOo's near feature-parity with Word a lot louder and ODF's importance as a format a lot less if I were Sun. But that's just me.